Largest Earthquakes In The Last Century History Essay

An earthquake is felt to be occurred when the ground surface underneath our feet seems solid and firm, which is in contrast to the fact; the planet's surface being dynamic grid of slowly moving sections which are actually called as the 'tectonic plates'.

The actual mechanism of the occurrence of the earthquake is quite complex. These movements are imperceptible to humans, and the only way it is shown is on the geological time scales, which is even notable if two adjacent continents are drifting apart at the rate of just five minutes centimetres per year. These movements subsequently cause tension in the earth's crust and when this tension reaches its threshold, some part of the crust gives way, and thus, shifts suddenly and violently. This usually happens along a point of fault or a fracture of the earth's crust, and this shift is then termed as an earthquake. The extent of damage caused by an earthquake mainly depends upon on its focus point. 90% of earthquakes occur along borders of tectonic plates only, but some are more massive, causing destruction in even stable regions up to thousands of kilometres from the plate edges. The power of destruction of an earthquake, though still remains in close relation with the depth of its focus point, causing 'shallow-focus' events in most of the earthquakes. Earthquakes can also occur beneath oceans, and these oceanic quakes are equally massive and destructive, stimulating enormous tidal waves, or even tsunamis. Earthquakes are measured with a device which is known as a seismograph, on a Richter’s Scale, measuring on a scale of 1 to 10, each step in the scale, indicating a tenfold increase in the energy of earthquake.

Some of the worst and deadliest earthquakes of the century, measured on this scale, that have left significant impressions on history are:

1976, Tangshan China.

1927, Xining China.

1920, Gansu China.

1923, Yokohoma Japan.

1970, Northern Peru.

2001, Gujarat, India.

1990, Northwest Iran.

2003, Southeast Iran, Bam.

1939, Erzincan Province, Turkey.

1939, Chillan, Chile.

1988, Turkish- USSR Border.

1978, Northeast Iran

1976, Guatemala

1906, Santiago/Valparaiso, Chile.

1905, Kangra, India.

1907, Central Asia.

1934, India/Nepal

1985, Michoacán, Mexico.

1995, Kobe, Japan.

1960, Chile.

1998, Northeast, Afghanistan.

1933, Sanriku, Japan.

1966, Varto, Turkey.

1975, Turkey

1950, India/Assam/Tibet.

1997, Northern Iran.

1946, Tonankai, Japan.

1999, Turkey.

1983, Turkey.

1946, Turkey.

1999, Western Colombia.

1970, Gediz, Turkey.

1906, Colombia.

2010, Haiti.

1999, Taiwan.

2010 Haiti

Location

The location of the earthquake was the capital of Haiti, Port-au-Prince, its epicentre being near the town of Léogâne, approximately 25 km (16 miles) west of Port-au-Prince. Dimensions of extent of the earthquake were:

25 km (15 miles) WSW of PORT-AU-PRINCE, Haiti

130 km (80 miles) E of Les Cayes, Haiti

150 km (95 miles) S of Cap-Haitian, Haiti

1125 km (700 miles) SE of Miami, Florida

Date and Time of Occurrence

The earthquake occurred at 16:53 local time on Tuesday, 12 January 2010.

Magnitude and Extent of Destruction

The magnitude of the earthquake was 7.0 and the causalities included both civilian and government officials, locals and foreigners –the majority being the Haitian civilians, the death toll being recorded over 150,000 in the capital area alone, whereas the number of injured people was estimated to be 300,000.

Aftershocks

There were eight aftershocks recorded by The United States Geological Survey (USGS) in the two hours after the main earthquake, with magnitudes between 4.3 and 5.9, and several more within the same week, sixteen of them having a magnitude greater than 5.0, however, the strongest one was recorded on January 20, having a magnitude of 5.9.

A tsunami warning was issued too, but it was of very less significance, and so, was cancelled.

Tectonic Mechanism

According to a presentation held by the UConn’s Geology Club, “It was so destructive because of the location, depth and magnitude of the earthquake. Earthquakes occur after a continent’s tectonic plates suddenly shift, which causes trenches and mountains to form. The Caribbean plate and the North American plate shifted in Haiti, causing the earthquake.”

Summary

The earthquake that occurred in the region of Haiti on Jan 12, 2010 was a magnitude of 7.0, with massive destruction not only in the main region, but also areas surrounding it. The Haitian civilians and other people affected owe its hazard to location, depth and magnitude of the earthquake.

The map below indicates the hazard of the earthquake on the seismic map, according to the Global Seismic Hazard Assessment Program.

2001 Gujarat, India

Location

The location of the earthquake was 23.41N 70.23E in the region of Gujarat, India. Its epicentre was at Bhuj (23.6° N 69.8° E) Gujarat, India.

Date and Time of Occurrence

It occurred in January 26, 2001. At 08:46 AM.

Magnitude and Extent of Destruction

The magnitude of the earthquake was recorded to be between 7.6 and 8.1 on the Richter scale. The death toll reached around 20,000 people (including 18 in South eastern Pakistan) and the number of injured people and the destroyed homes was 167,000 400,000 respectively. Extent of spread of the shockwaves was 700 km and 21 districts. Altogether 600,000 people were recorded to be left homeless.

Aftershocks

Aftershocks were recorded in India with magnitude of 7.6 on January 26, 2001.

Tectonic Mechanism

The mechanism of this earthquake is thought to due to the result of stored energy in a collision margin. It is actually believed to be an inter plate earthquake one that occurred at a distance from any plate boundary where plate tectonics create most earthquakes, so the area was not well prepared.

Summary

The Gujarat, India earthquake, having a magnitude recorded between 7.6 and 8.1 had its effects in nearby surroundings, and affected hundreds and thousands of people leaving them homeless, by destroying around 90% of homes and millions of other buildings, including schools, offices, hospitals and tourist attractions.

2005, Pakistan

Location

The earthquake hit the area of Azad Kashmir, its epicentre being near the city of Muzafferabad, AJK. The dimensions of its extent are

105 km (65 miles) NNE of ISLAMABAD, Pakistan

115 km (70 miles) ESE of Mingaora, Pakistan

125 km (75 miles) WNW of Srinagar, Kashmir

165 km (105 miles) SSW of Gilgit, Kashmir

Date and Time of Occurrence

It occurred at 08:52 AM Pakistan Standard Time, on May 8th, 2005.

Magnitude and Extent of Destruction

On the Richter’s scale, the magnitude of this earthquake was measured to be 7.6 and causalities even in surrounding areas, given in the table below:

2005 Kashmir earthquake casualties

Location

Dead

Injured

NWFP, Pakistan Pakistani Kashmir

73,338

100,000

Indian Administered Kashmir

1,360

6,266

Afghanistan

4

14

Total

74,500+

106,000+

Aftershocks

More than 20 aftershocks were reported ranging from 4.5 to 6.3 in magnitude, within 18 hours following the main shock.

Tectonic Mechanism

The unstable mountains of Northern Pakistan were very vulnerable to extensive landslides, when the earthquake struck the region. Moreover, the Northern, Western and Southern Pakistan, Kashmir and Northern India and Afghanistan are along zones of increased seismic activity. This increased seismic activity occurs near the regions of thrust faulting, and all these add up to make the areas more prone for earthquakes.

Summary

The earthquake of Kashmir, Pakistan that adversely affected the lives of millions of people occurred on October 8th, 2005, was the biggest damage that had ever occurred in Muzafferabad area, destroying entire villages, disrupting the infrastructure of Muzafferabad. The recorded loss of number of buildings was 32, 335, and the number of people that suffered from homelessness went up to 4 million.

1990, Northwest Iran

Location

The 1990 Manjil-Rudbar Earthquake caused extensively spread damage within a radius of one hundred kilometres of its epicentre, which was at 36.957°N 49.409°E near the City of Rasht and about two hundred kilometres northwest of Tehran.

Date and Time of Occurrence

The massive destruction occurred at 00:30 AM on June 21, 1990 UTC.

Magnitude and The extent of Destruction

The Richter’s scale recorded the earthquake to have a magnitude of 7.4 on the seismic scale. The reported casualties, were around 40,000-50,000 death toll and 60,000 people injured. Extensive damage and landslides in the Rasht-Qazvin-Zanjan area caused 400,000 or more people to get homeless. Moreover, almost all of the buildings were destroyed in the Rudbar-Manjil area.

Aftershocks

After the main quake, several aftershocks were reported, mostly in the region of the North-western Iran, including Arak, Bakhtaran and Tabriz.

Tectonic Mechanism

Unfortunately Iran is one of the most seismic active countries of the world, with at least 90% of its region falling in the active seismic zone, known as the Alpine Himalayan Belt. This contributes to the high vulnerability of this region for natural hazards like earthquakes and destruction.

Summary

The region of North Western Iran is vulnerable to increased seismic activity and subsequently, prone to massive earthquakes. The Manjil-Rudbar Earthquake resulted in thousands of innocent people to lose their lives, as well as homes. The earthquake also had widespread dimensions of surrounding areas’ damage and aftershocks of varying magnitudes.

1999, Taiwan

Location

The massive hits of earthquakes struck the Central Taiwan at a depth of 1.1 kilometres.

Date and Time of Occurrence

The earthquake disaster began on Monday, September 20th 1999, and the series that included thousands of aftershocks preceded the first event.

Magnitude and The Extent of Destruction

An official estimate of of 2,161 deaths, 8,736 injuries was listed, with approximately 150 people still not found. The largest earthquake out of the disastrous series was measured to be 7.6 on the seismic scale by the Richter’s scale.

Aftershocks

The first event of the series was followed by more than 9,000 aftershocks.

Tectonic Mechanism

Taiwan is located in the same tectonic position at the point where the South China Sea is sub ducting beneath the Luzon arc. Since the collision with the continental slope of China started only 4 million years ago, subsequently only the sediment has been accreted, and that caused Turkey to be more prone to earthquake hits.

In the more matured collision zone like Himalaya, the mechanical plate boundary (which is the Main Boundary Fault in Himalaya) is located far from the suture zone (the Indus-Zhanpo suture zone In Himalaya). Similarly in the case of Taiwan, most of the plate motion is exhausted at the thrusts and the decollement beneath the Western Foothills. The suture zone, i. e. the Longitudinal Valley, however has not died yet.

Thus, the structure of the Coastal Plain - Western Foothills should be rather regarded as a subduction zone, as compared to a collision zone. Therefore 1999 Taiwan earthquake should be actually regarded as a subduction zone earthquake. The slip direction of the Harvard CMT solution is different only by 5 degrees from the Eurasian - Philippine Sea plate motion, which is expected from Seno et al.

Summary

Taiwan has been hit by earthquakes quit a few times, and that too, with significant destruction and proving to be hazardous for millions of people. The reason lies with the face that it’s located in an earthquake ‘danger zone’.

1976, Tangshan, China

Location

It occurred in the north-eastern part of China, near the coast. The epicentre was located at about 140 kilometres southeast of Beijing, in the vicinity of Tangshan.

Date and Time of Occurrence

This natural disaster occurred on July 28th, 1976, at 03:42AM local time.

Magnitude and the Extent of Destruction

This earthquake is believed to have the highest death toll of the 20th century, ranging from 242,419 to 779,000 dead people.

Its magnitude recoded on the Richter’s scale by seismicity was 7.8. Its destruction and damage shook China so massively, that for China, 1976 was called the ‘Year of Curse’.

Aftershocks

A massive aftershock was recorded 16 hours after the main earthquake, having the magnitude of 7.6, which further increased the death toll to even a larger number.

Prediction

This earthquake was already predicted by the State Seismological Bureau (SSB) fifteen days before the actual disaster, and an observation of rising and falling of the water level of a well in a village near Tangshan was also made. This was observed one day before the main earthquake hit, three times a day. Another point of significance in this regard was the beginning of spouting of gas out of a well in another village on July 12, which increased on July 25 and further on July 26.

Summary

The earthquake in Tangshan, also known as ‘The Great Tangshan Earthquake’ was a big disaster for China, causing millions of people to lose their lives, as well as their homes and the whole city suffered by the destruction of buildings, offices and the whole country’s infrastructure. It is still regarded as one of the history’s most significant earthquake, and is compared to earthquakes of its kinds

Deadliest earthquakes[1]

Rank

Earthquake

Magnitude

(MW)

Country

Date

Fatalities

1

Shaanxi

8

China

January 23, 1556

830,000

2

Tangshan

7.8

China

July 27, 1976

242,000

3

Indian Ocean

9.1–9.3

Indonesia

December 26, 2004

~230,210

4

Aleppo

8.5

Syria

October 11, 1138

230,000

5

Haiti

7

Haiti

January 12, 2010

222,570

6

Danghan

?

Iran

Dec22

200,000

This above picture shows the bending of railway rails on the Beijing-Shanhaiguan railway that passes through Tangshan, due to liquefaction caused by the earthquake of Tangshan.

In conclusion, it is proved by past evidences in history how earthquakes have always been a natural but very deadly hazard for the mankind. Some areas are prone to earthquakes and they are already predicted to go through such damage, due to their geographical location, while some have to face this strike suddenly. Whatever the case, the aftermath is very deadly, and it takes years and years for countries and governments to recover, while sometimes, it becomes even impossible.